The present invention relates to a liquid laundry detergent and pretreatment composition for difficult to remove stains. The invention combines in a single product an effective laundry detergent with a pre-treatment for removing stains. The pretreatment preparation provides a viscosity increase assuring the consumer that the laundry pretreatment has been activated and insuring additional contact time with the stain for improved performance.
Liquid laundry detergents have been known to provide improved performance when directly applied to heavily soiled or stained areas of laundry items prior to washing. This, however, requires additional sorting and pretreating before washing. Some pretreatment products have addressed this inconvenience by allowing consumers to pretreat the soiled laundry at any time before washing. Liquid laundry detergents do not currently offer this convenience.
It is known that enzymes require sufficient water for effective performance. Unfortunately, they cannot be stored in aqueous solutions for extended time periods at an effective concentration without degrading. Therefore, the enzymes in liquid laundry detergents and pretreatments cannot be fully activated without additional water in a presoak or wash cycle.
Presoaking can be an effective means of improving performance on heavy soils and stains. This method, however, does not achieve the direct contact and higher concentration advantages of laundry pretreatment products as does direct application of liquid laundry detergent. It is also considered inconvenient by many consumers.
The present invention addresses these shortcomings by providing a liquid laundry detergent that can be converted into an effective pre-treatment formulation. In particular, the composition of the present invention will, when diluted with water, form a gel that will not run off a stained garment to which the product of the present invention has been applied.
The present invention therefore provides a liquid laundry detergent composition that includes an enzyme especially selected for its performance on protein-type stains. The detergent has been formulated with a minimal amount of water and a stabilizer for a long shelf life for the sensitive enzymes of the formulation. The product has been formulated such that while it is a liquid in its container, it turns into a gel of controlled viscosity upon dilution with additional water. The resulting gel effectively adheres to garments to ensure continuous contact with the soil until laundered. The transformation from a liquid to a gel is also effective in signaling to the user that the enzyme in the product has been activated by addition of sufficient water and is now working to remove stains.
In general therefore, the composition of the present invention includes from about 35% to about 75% of one or more nonionic surfactants, from about 10% to about 25% of one or more anionic surfactants, from about 5% to about 15% of a nonionic solubilizing agent, and from about 0.1% to about 1.5% of one or more enzymes, wherein the composition contains less than about 25% water. The composition is a liquid but when diluted with water in a ratio of 9:1 to 1:1 (composition to water), the composition forms a viscous gel.
In one embodiment, the present pretreatment composition consists essentially of from about 35% to about 75% nonionic surfactant, from about 10% to about 25% anionic surfactant, from about 5% to about 15% nonionic solubilizing agent, and from about 0.1% to about 1.5% enzyme, in which the above composition is a liquid containing less than about 25% water, and where dilution with water in a ratio of from about 9:1 to about 1:1 (pretreatment composition:water) forms a viscous gel useful in treating stains on clothing.
The composition of the present invention may also contain one or more surfactants and dispersants to aid in the breakup and solubility of the gel when it is further diluted with water, as when the treated garment is put into a washing machine for further laundering. Other ingredients may also be present to aid in gel formation, lend greater surfactancy, enhance aesthetics and utility of the detergent, and to aid in solubilizing the non-ionic surfactants in aqueous solutions.
Another aspect of the present invention is directed to a method of pretreating stained garments using the composition of the present invention. In this aspect, the composition is diluted with water, applied to a portion of fabric containing a stain, and allowed to remain on the stain for a period of time before washing. In a preferred embodiment, the composition is allowed to remain on the stained garment for at least ten minutes. It appears, however, that most of the benefit of using such a pretreatment is reached after thirty minutes. Therefore, extended treatment is not necessary. No detrimental effects on detergency, however, were observed when the pretreatment contact time exceeded twenty-four hours.
All percentages set forth in the following specification and appended claims are by weight unless otherwise noted.